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3 First Steps in TinyOS Programming  What files needed in an application directory?  How to use the Timer and LED components?  How to compile and download an application to a Mote?  Application: MyApp in /MoteWorks/apps/tutorials/lesson_1/

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4 About MyApp This timer application uses one of the timers on the ATmega128L Mote.  The timer will be set to fire continuously every second and the Mote red LED will toggle on and off to show this visually. So why go through the trouble of this program?  This is TinyOS’ version of “Hello World”  To help you learn TinyOS and nesC programming methods

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6 Lab Outline 1.Enter/review all necessary code and auxiliary files 2.Build (compile) and download the application 3.Take a closer look at the code and auxiliary files You need  One MICA Mote: standard editions of MICA2 (MPR4x0) or MICAz (MPR2400).  One gateway/programming board: MIB510, MIB520, or MIB600 and the associated hardware (cables, power supply) for each  A Windows PC with MoteWorks installed

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7 MyApp Application Review  The application folder (directory) is where all your top-level application code and associated files will be stored.  Navigate to the directory /MoteWorks/apps/tutorials/lesson_1

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8 Seven Common Files in an Application Directory 1.Makefile 2.Makefile.component 3.Top-level application configuration written in nesC 4.Top-level application module written in nesC 5.sensorboardsApp.h file (not seen here, but typical for applications using sensors and GPIO) 6.appFeatures.h (optional) 7.README (optional, but highly recommended)

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10 MyApp – Makefile.component This file describes the top level application component, MyApp, and the name of the sensorboard we are going to use. The sensorboard reference tells the compiler we want to use the nesC components for accessing the sensor devices on that board.  The collection of those components is also known as a “driver” COMPONENT=MyApp SENSORBOARD=mts310

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14 Main – the scheduler for TinyOS A TinyOS application = configuration (wiring) of new and existing components + the component Main. Main, the scheduler, runs the tasks created by those components. A TinyOS top-level application must have the Main component in its configuration.

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15 Main cont’d  Main is a component that is executed first in a TinyOS application.  The command Main.StdControl.init() is the first command executed in TinyOS followed by Main.StdControl.start().  StdControl is a common interface used to initialize, start, and stop TinyOS components. configuration Main { uses interface StdControl; } implementation { components RealMain, PotC, HPLInit; StdControl = RealMain.StdControl; RealMain.hardwareInit -> HPLInit; RealMain.Pot -> PotC; }

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17 Parameterized Interfaces (1 of 2)  There may be multiple users of a component  One Timer component but many users with different event time requirements  When a Timer “fires” which component should be signaled? TinyOS handle this using parameterized interfaces  Multiple instantiations of a component’s Interface  Parameter specifies the specific instance

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18 Parameterized Interfaces (2 of 2)  A parameterized interface allows a component to provide multiple instances of an interface  Parameterization (or indexing) is set by a compile- time value provides interface Timer[uint8_t id];  Total number of instances permitted may be limited by implementation

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19 nesC Concepts – Unique Instances To make sure your instance parameter is not used by someone else, use unique(“astring”)  Generates an 8-bit identifier from the string given as an argument.  Multiple components using timer[unique(“Timer”)] are each guaranteed to get a signal associated with their specific timer settings. All components must use the same “ astring ”  In our app ”Timer” is used as the astring

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21 MyApp – Top Level Module The application’s module is located in MoteWorks/apps/tutorial/lesson_1/MyAppM.nc  The function of this code is to start a timer and toggle the red LED on the Mote.

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22 MyApp – Top Level Module /** * This module shows how to use the Timer and LED components **/ module MyAppM { provides { interface StdControl; } uses { interface Timer; interface Leds; } The MyAppM module provides the interface StdControl.  To provide an interface means that MyAppM must implement that interface.  As explained earlier, this is necessary to get the MyApp component initialized and started. The first part of the code states that this is a module called MyAppM and declares the interfaces which are prefaced by the keywords provides and uses. 1 of 3

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23 MyApp – Top Level Module /** * This module shows how to use the Timer and LED components **/ module MyAppM { provides { interface StdControl; } uses { interface Timer; interface Leds; } In many nesC applications, it is common to call a function periodically.  Done by means of a timer. We also want to use one of the LEDs, so we use an interface to the LED The name for the interface for a timer is, conveniently enough Timer. The name for the interface for an LED is Leds. 1 of 3

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24 nesC Interface – The StdControl Interface (review) The StdControl interface (like the component Main ) must always be implemented at the top-level application.  The StdControl interface provides the basic functionality for the TinyOS application to be initialized, started and stopped. StdControl is like a power switch to turn on and off components  Also does boot time initialization StdControl should not be used for continuous processing  Use a timer instead

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25 StdControl Interface Details In /MoteWorks/tos/interfaces/StdControl.nc StdControl defines three commands : init(), start(), and stop().  init() is called when a component is first initialized  start() is called to execute a component  stop() is called when a components is stopped. init() can be called multiple times but will never be called after either start() or stop() is called. interface StdControl { command result_t init(); command result_t start(); command result_t stop(); }

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26 Mote About the Timer Interface interface Timer { command result_t start(char type, uint32_t interval); command result_t stop(); event result_t fired(); Here we see that Timer interface defines two commands  start() and stop() commands and one event  fired() event What is “ result_t ”?  It is the data type for the status value returned by a command or event.  This status value is either SUCCESS or FAIL.

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27 Mote About the Timer Interface (cont’d) interface Timer { command result_t start(char type, uint32_t interval); command result_t stop(); event result_t fired(); The start() command is used to specify the type of the timer and the interval at which the timer will expire.  The unit of the interval argument is millisecond. The valid types of timers  TIMER_ONE_SHOT  Ends after the specified interval  TIMER_REPEAT  Goes on and on until it is stopped by the stop() command.

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28 MyApp – Timer interface (cont’d) interface Timer { command result_t start(char type, uint32_t interval); command result_t stop(); event result_t fired(); How does an application know that its timer has expired?  When it receives an event. What is an event?  A signal from the implementation of an interface that something has occurred.  In this case, the fired() event is signaled when the time interval has passed. This is an example of a bi-directional interface  An interface can both provide commands that can be called by users of the interface, and signal events of call handlers implemented by the user.  Remember: A module that uses an interface must implement the events that this interface uses.

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35 MyAppM.nc – Key Lessons  The heart of most TinyOS applications is Timer.fired()  Compare to C where main() contains a while loop  A while loop in StdControl.init() would freeze the system and block all tasks  The proper way to centralize processing in TinyOS is to start a repeat timer (with REPEAT_TIMER ) and implement logic in Timer.fired().

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37 Compiling and Flashing the Mote 1.Now that you have reviewed all the application files, you can proceed with the compilation and flashing of the Mote  You need to be in the.nc of the app file you want to compile and program before you can execute shell commands from Programmer’s Notepad. 2.Attach one Mote to a Programmer/Gateway Board  One of MIB510, MIB520, MIB600  One of MICAz, MICA2 3.Compile your application:  Select Tools > make mica2 (or make micaz or make mica2dot)  The “Output” section of the Programmers Notepad will print the compiling results.